The present invention relates generally to ionic metallic deposition onto material.
There are many problems to be overcome in the metalizing of materials. Conventional methods for metalizing, for example silverizing, often result in uneven coating, clumping and flaking of the silver. Autocatalytic baths often result in xe2x80x9cdead zonesxe2x80x9d where no metal application occurs.
Metalized materials are fiequently used in the aeronautic industry. The military is aerospace industry has ongoing research programs to address the issues of impedance, resistance, RF resonance, RFI (radio frequency interference)xe2x80x94EMI (electromagnetic interference) shielding, conductivity levels, low observability applications, thermal signature reduction and transfer, attenuation of a variety of signal types, and infrared signature reduction requirements.
Conventional methods for metalizing materials result in significant weight gain to a material, which is undesirable. For example, there are no adequate methods for metalizing air-borne particulate material in such a way that the particulate material remains light enough not to be weighed down by the force of gravity.
The ability to coat the surface with a conductive layer has value in a wide variety of technologies and applications. For example, a conductive or semi-conductive layer disposed on a surface of a dielectric material to form a composite system can be used to control the tendency of the composite system to transmit, attenuate, or reflect electromagnetic radiation incident on a surface of the composite system. Although various approaches have been taken to coat dielectric substrates with conductive layers, each of the existing method has limitations. Accordingly, there is a need to develop an improved method for disposing a conductive layer on a dielectric substrate.
Further, it is desirable to provide a process for deposition of metals onto a material that results in an even application of metal onto the material. There is a need for a process that allows for a very fine layer of metallic application on a microparticulate, so as to reduce the amount of metal required.
It is an object of the present invention to obviate or mitigate at least one disadvantage of previous processes for metal deposition onto microparticulate.
The invention provides a process of multi-phased shifted ultrasonic travelling wave ion stimulation for autocatalytic deposition of metal onto microparticulate material at the resonant frequency of the material. Advantageously, metal ions are deposited evenly onto the material using this process. Further, the invention provides metalized micropatticulate materials, such as Nylon(trademark), Kevlar(trademark), Zylon(trademark), or any polymeric material that can be formed in a microparticulate size. The invention is useful for a variety of military, avionic, and industrial applications.
The purpose of this invention is to control and accelerate the transfer rate of a metal, such as ionic silver, onto sensitized microparticulate material in such a manner that permits uniformly fine deposition of the metal. By controlling the depositional thickness, the weight of the metal added to the microparticulate does not weigh down the miarticulate, thereby leaving it capable of remaining air-bome for a certain period of time. This process also permits the effective de-gassing of the autocatalytic medium, eliminating problems associated with depositional voids. In turn, the thickness and quality of the metal deposition on the microparticulate material, such as nylon, Kevlar or other polymers, controls the level of conductivity designated for the end product.
The sensitized microparticulate is constantly in motion relative to the metallic solution. Consequently, the microparticulate and the medium in which it is present are put in a constant and controlled flow toward each other. This eliminates depletion zones within the autocatalytic solution, which is a common problem with conventional methods of autocatalytic plating. Thus, when the sensitized microparticulate material is drawn through the metalizing solution at a controlled rate a constant deposition of metal is applied to the material.
Metalized microparticulate materials so formed can be used in a variety of applications, including the fields of military, aerospace, or industrial and commercial products.
Further, according to the invention there is provided a method for coating a surface with metallized microparticulate in such a way that the microparticulate is either aligned, polarized or arranged randomly so as to attenuate a signal from the surface. A method for coating a surface with a coated microparticulate fibers is disclosed herein in which microparticulate being generally oriented perpendicular to the surface. The method comprises spraying the coated microparticulate from a charged nozzle onto a surface having an opposite charge to the charge of the nozzle. Optionally, the surface may be coated with two or more layers of microparticulate, each of which layer of microparticulate is metallized with a different metal, so as to allow formation of a galvanic current A method is disclosed herein for creating a surface across which a galvanic effect is observed. To accomplish this, the surface is layered with a metallized microparticulate coated with a first metal, followed by a metallized microparticulate coated with a second metal. The first metal differs from said second metal, and at least one of said first metal and said second metal is coated onto microparticulate using the ultrasonic method disclosed herein